The invention discloses a four-phase and double-salient brushless direct current motor with symmetrical phase inductances. According to the four-phase and double-salient brushless direct current motor, a unit motor is of a novel 12 / 9 salient structure or a novel 12 / 15 salient structure, each excitation element is wound after spanning three stator poles, each stator coil of each phase stator winding is distributed at different positions, and the symmetry of the phase inductances is achieved by a mode of symmetrically distributing the four phase stator windings; the pole-arc coefficient matching size of motor stators and rotors is determined by theoretical analysis and emulation verification methods, so that the phase inductances of the motor are hoisted and decreased by an electrical angle of 180 degrees, the total permeance of exciting windings remain basically unchanged, the positioning torque of the motor is small, and the four phases are electrified at the same time to operate. In addition, the four phase stator windings are independent in pairs, so that the motor can operate by only using the two phases after one phase is in fault, and the fault tolerance performance is favorable. Moreover, the total permeance of the exciting windings is unchangeable, so that the four-phase and double-salient brushless direct current motor has the advantages of small positioning torque and the like.